/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.cassandra.stargate.transport.internal;

import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.LoadingCache;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.EnumMap;
import java.util.List;
import org.apache.cassandra.stargate.transport.ProtocolVersion;

/** This class tracks the last 100 connections per protocol version */
public class ProtocolVersionTracker {
  private static final int DEFAULT_MAX_CAPACITY = 100;

  private final EnumMap<ProtocolVersion, LoadingCache<InetAddress, Long>> clientsByProtocolVersion;

  ProtocolVersionTracker() {
    this(DEFAULT_MAX_CAPACITY);
  }

  private ProtocolVersionTracker(int capacity) {
    clientsByProtocolVersion = new EnumMap<>(ProtocolVersion.class);

    for (ProtocolVersion version : ProtocolVersion.values()) {
      clientsByProtocolVersion.put(
          version,
          Caffeine.newBuilder().maximumSize(capacity).build(key -> System.currentTimeMillis()));
    }
  }

  void addConnection(InetAddress addr, ProtocolVersion version) {
    clientsByProtocolVersion.get(version).put(addr, System.currentTimeMillis());
  }

  List<ClientStat> getAll() {
    List<ClientStat> result = new ArrayList<>();

    clientsByProtocolVersion.forEach(
        (version, cache) ->
            cache
                .asMap()
                .forEach(
                    (address, lastSeenTime) ->
                        result.add(new ClientStat(address, version, lastSeenTime))));

    return result;
  }

  List<ClientStat> getAll(ProtocolVersion version) {
    List<ClientStat> result = new ArrayList<>();

    clientsByProtocolVersion
        .get(version)
        .asMap()
        .forEach(
            (address, lastSeenTime) -> result.add(new ClientStat(address, version, lastSeenTime)));

    return result;
  }

  public void clear() {
    clientsByProtocolVersion.values().forEach(Cache::invalidateAll);
  }
}
